This invention relates to 2-substituted 7-haloindenes useful in coupling reactions to produce a wide variety of metallocene olefin polymerization catalyst intermediates and to metallocene catalysts derived from such intermediates.
Metallocenes which comprise indene systems are well known xcex1-olefin polymerization catalysts. Substitution patterns in such indene systems significantly influence poly-xcex1-olefin properties, including tacticity and molecular weight.
Spaleck, et al., Organometallics (1994) 13:954-963 describes bridged zirconocene catalysts including indene systems illustrated by Compound 4 of xe2x80x9cScheme 1xe2x80x9d (p. 955) which yield highly isotactic polypropylene when used with methylaluminoxane as a cocatalyst. As shown by xe2x80x9cScheme 2xe2x80x9d, Compound 10, Spaleck""s synthesis requires an expensive 2-(bromomethyl) biphenyl starting material.
This invention provides a more cost effective synthesis of metallocene catalysts which comprise indene systems.